Lamp



e. H. ROLFES.

LAMP.

APPLICATION FI LED APR- 28, I921.

Patented June 6, 1922;.

2 SHEETSw-SHEET l.

6190/" 6 $5 W QMJ G. H. ROLFES.

' LAME] APPLICATION FILE-D APR. 28. 1921.

1,418,832. PatentedJune 6,1922.

2 SHEETSSHEET 2.

unrrsn srarss "KENT enonsn i-I. norrns, or s'r'. LOUIS, Missonm, ,assienon 'ro nANnLAiv-BuoK MANU- raoruarne COMPANY, orsr. Lou s, Mrsso'unr, a oonrona'r on or MISSOURI.

LAMP,

Application aiea'a m as,

T0 aZZ 107mm may concern:

Be it known. that I, Gnonon H. RoLrns, a. citizen of the United States of America, and a resident of the city of St. Louis, in the State of Missouri, have invented certain new and useful Improvements in Lamps, of which the following is a full, clear, and exact description, reference being hadto the ac companying drawings, forming a part of this specification.

This invention relates to improvements in lamps, and especially to a lamp having a base provided with a socket for the reception of a supporting staff. The main object is to provide a strong, simple. and inexpensive means whereby lamps of this kind can be adapted to accurately lit the lamp-supporting staffs.

Prior to this invention, switch lamps, and some other lamps used in connection with railroad signals, have been supported by rotary staffs, and these lamps should be firmly supported in true vertical positions. The supporting staff is usually provided with a tapered upper end, non-circular in cross section, and the lamp base has a socket in which the tapered end of the staff is inserted. It is economical to make th lamp base of ordinary cast iron, or malleable iron, but such castingsare not accurate enough to properly lit the lamp supporting staffs. Heretofore it has been necessary to accurately finish the castings for the purpose of making the sockets conform to the tapering staffs, and lamp manufacturers have carried in stock numerous different castings adapted to be machined and otherwise finished to fit supporting staffs of different dimensions. The cost of the labor involved in finishing these castings is an important item, and it has been very difficult to obtain the desired accuracy in tinishing the staff-receiving sockets. The socket should firmly engage thetapered end of the supporting staff, so as toprovide a firm support for the lamp, and the lamp should be supported in a true vertical position parallel with the axis of the staff. 7 l

In accordance with thepresentinvention, the lamp base may be an ordinary rough casting and it is not necessary to smooth the inner surfaces of the staff-receiving socket in the rough casting. In fact, an advantage Specification of Letters Patent.

Patented June 6, 1922.

1921. Serial No. 465,078.

is gained by leaving these surfaces in a rough condition. Furthermore, the same pattern may-be used in making base castings intended to receive supporting staffs of difi'erent dimensions, so it is not necessary for the lamp manufacturer to carry a large stock of different base castings.

Briefly stated, the lamp base may be an ordinary rough casting provided with a tubular mold member which may have rough inner faces. A smooth metal core, conforming to the shape and dimensions of any selected lamp-supporting staff, is inserted into the tubular mold member, and the space between the core and the inner faces of the mold member is then filled by a body of molten metal. When this body of metal becomes cool and hard, it will be interlockedwith the rough inner faces of the mold member which forms part of the lamp base, and the entire base can be easily withdrawn from the smooth tapering metal core. The resultant product is a lamp base having a staff receiving socket conforming precisely to the shape and dimensions of the upper end of the staff.

An object is to very securely anchor the adapter which is formed by pouring molten metal'into the tubular mold member. As the molten metal becomes cool and hard it shrinks in the'mold member, and as a conse quence, the cool'castii'ig is smaller than the internal dimensions of the mold. Obviously, this shrinkage or contraction of the adapter casting would tend to loosen the same in an ordinary mold member; My object is to anchor the adapter casting in such a manner that it cannot be displaced in any direction relative to the mold member. 7

In the preferred form of the invention, the tubular mold member is provided with anchoring ribs on its inner face, said ribs be ing formed iirzig-zag lines and provided with beveled faces onto which the adapter casting is shrunk. Owing to the peculiar manner in which these anchoring ribs are formed, they are very firmly gripped at numerous oppositelydisposed points, so as to securely interlock the adapted casting with the ribbed mold member.

F I is a side elevation, partly in section, illustrating a switch lamp embodying the features of this invention.

Fig. H is an enlarged vertical section illustrating the method of torming the adapter in the lam base.

Fig. H is a top or plan view f the elements shown in Fig. II.

Fig. IV is a fragmentary perspective view illustrating the peculiar ribbing in the mold member.

Fig. V is an enlarged vertical section through the mold member and adapter casting, the spaces between the mold and casting being exaggerated to illustrate the manner in which the casting is shrunk onto the ribs.

Fig. VI is an enlarged vertical section, showing one of the ribs in the mold mem her.

A designates the body of a switch lamp including a housing 1. provided with a bottom wall .2. B designates a base arranged below and secured to the lamp body.

The base B includes a central tubular mold member 3 non-circular in crosssection, arms at extending from the upper portion of said mold member, and supporting wings 5 extending from the corners of the mold mem-' her. The lower edges of wings 5 are preferably .[iush with. the lower edges oi? the mold member 3, so as to allow the lamp to be seated on a. horizontal surlace when it is not in use. The arms l lie within the housing 1 at points below the bottom wall 2, and said arms are secured to the housing by means ofrivets 6. The lamp base. including the mold member El. may be made oi ordinary cast iron. or malleable iron.

designates a. tubular adapter located in the mold member 3 and provided with a non-circular tapering opening conforming to the upper end of a central supporting staff D. This staff D may be considered as the rotatable staff of a railway switch stand.

In H and ill I have illustrated a method oi nmking the adapter (l. 7 designates a table on which the lamp base B is seated. and D designates a metal core located in the mold member 3 of the lamp base and provided at its lower end with a circular head 8 which lies within the table 7. Gentering lugs 9 are secured to the table 7 at points on opposite sides ot the core D. These lugs 9 are adapted to engage the wings 5 and mold member 3. as shown in the drawings. so as to enable the base casting to be easily located in the proper position on the table 7.

To form the adapter C, molten metal is poured into the mold member 3 while the core D is positioned as shown in II and III. W hen this metal becomes hard, the lamp base can be very easily withdrawn from the smooth tapering metal cor D. This core conforms to the taper of the supporting staff D, so the smooth inner face of the adapter will accurately lit the supporting staff. The outer face of the adapter C is in direct contact with the rough walls oi the mold member 3, so the adapter is securely interlocked with the various projections and other irregularities on the rough inner face oi the mold member.

I will now describe the anchoring ribs onto which the adapter casting C is shrunk to positively prevent displacement of the adapter relative to the mold member 3. The walls of the noncircular mold member 3 are preferably flat and these walls surround the adapter casting. In. the preferred form of the invention. a series of endless anchoring ribs 10 are formed integral with the mold member 3 so as to project from the inner face of the mold, said ribs being V-shaped in cross-section, and each rib being formed in a continuous zig-zag line extending across the inner faces oi? the mold walls. The rib elements on each wall. are inclined so as to extend diagonally of the Hat wall, and although the rib elements on any one of the walls may be parallel with each other, they preferably lie at an angle to the rib elements on the other walls.

Attention is directed to the peculiar manner in which the adapter casting U will grip the ribs 10 during the cooling process. This is suggested by Figs. V and VI. As a result of shrinkage, the adapter casting (1 will contract vertically and firmly grip the ribs at K. (Fig. V), leaving slight spaces atZ. The anchoring ribs are thus securely gripped to prevent vertical displacement of the adapter casting. .llurthermore, the adapter casting will shrink horizontally while it is in contact with the inclined anchoring ribs Ill). the result 0'! this horizontal shrinkage being suggested by arrows and shading in l? Vi. \Vhile the metal is contracting along the inclined ribs 10 the top and bottom of each in.- clined rib is gripped at the points indicated by the shaded portions of Fig. VI. .rissurning that the contracting metal is displaced as indicated by arrows in l ig. VI, the bottom of the inclined rib it) will be gripped at the right hand side, while the top face of the same inclined rib will be gripped at the left side of Fig. VI.

The particular manner in which these peculiarly formed ribs are gripped by the casting 0 cannot be accurately illustrated, but it will be apparent that the cast metal is shrunk onto the oppositely inclined faces at numerous points, so as to securely and permanently interlock the adapter casting with the mold member, thereby positively preventing any loosening oi the adapter casting in the mold member.

A study of the peculiar action at the anchoring ribs 10 will show that an advantage is gained by making the mold member 3 in the form of a tube surrounding the adapter casting G, for the tendemry to displace the casting; from one wall of the mold is opposed by the other walls. The inclined ribs 10 do not tend to displace the casting from its central position in the mold, and the oppositely disposed ribs on the several walls of the surrounding mold prevent any undesirable displacement of the casting.

I claim:

1. A lamp having a base including a tubular mold member provided with anchoring means on its inner face, and a metallic tubular adapter cast in said mold member, said tubular adapter being shrunk onto said anchoring means so as to securely interlock the adapter casting with said mold member.

2. A lamp having a base including a tubular mold member provided with anchor ing ribs extending inwardly from its inner face, and a metallic tubular adapter cast in said mold member, said tubular adapter being shrunk onto said anchoring ribs so as to securely interlock said tubular adapter with said mold member.

3. A lamp having a base including a tubular mold member provided with oppo sitely disposed anchoring ribs extending inwardly from its inner face, said oppositely disposed anchoring ribs being formed at an angle to each other, and a metallic tubular adapter cast in said mold member, said tubular adapter being shrunk onto said an choring ribs so as to securely interlock said tubular adapter with said mold member.

4. A lamp having a base including a tubular mold member provided with anchoring ribs extending inwardly from its inner face, said anchoring ribs hating oppositely disposed inclined wedging faces, and a metallic tubular adapter cast in said mold member, said tubular adapter being shrunk onto said oppositely disposed inclined wedging faces, so as to securely interlock the adapter casting with said mold member.

5. A lamp having a base including a tubular mold member provided. with anchoring ribs extending inwardly from its inner face, said anchoring ribs being formed in diagonal lines on said inner face, and a metallic tubular adapter cast in and surrounded by said mold member, said tubular adapter being shrunk onto said anchoring ribs soas to securely interlock said adapterwith said mold member.

6. A lamp having a base including a tubular mold member provided with anchor-.

ing secured thereto,'said base casting including a central tubular mold member, the walls of said mold member being Hat and provided with a series of endless anchoring ribs projecting from their inner faces, said ribs being V-shaped in cross-section and each rib being formed in a continuous zigzag line extending across the inner faces of said walls, the rib elements on each of said walls being inclined and at an angle to the rib elements on the other walls, and a tubular adapter comprising a hollow core cast in said mold member, the outer face of said tubular adapter being in direct contact with inclined faces of all of said anchoring ribs so as to securely interlock said adapter with said mold member, and said adapt-er being provided with a non-circular tapering opening for the reception of a central supporting staff.

8. An article of manufacture comprising a base, a tubular mold member integral therewith, anchoring ribs on the inner walls of said mold member, said ribs being inclined relatively to the axis of said mold member, and a tubular metallic adapter cast in and surrounded by said mold member.

9. An article of manufacture set forth in claim 8 in which the anchoring ribs are inclined each to the other.

In testimony that I claim the foregoing I hereunto afiix mysignature.

GEORGE H. ROLFES. 

